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Re: spruce yard

Re: spruce yard

^ Seconded.

If you're concerned about the weight difference take 4 pieces of 3/4" square, with biased (45 degree) grain if possible, plane one of the corners down on each piece and glue it up hollow with the edge grain showing all the way around. Buy 6 feet of that elastic band stuff that's used for physical therapy, you can get it at the pharmacy, and cut it into 1" by 6 feet strips and wrap the 4 pieces with it to clamp while the glue cures. The yard will be the same weight, stronger and much more affordable. TIII glue will work just fine for that.

Re: spruce yard

If you plan to round it 1.5" is a bit skinny for a good lugsail yard and will tend to be awfully whippy - which makes it hard to design a sail that really works well on it. Something with a 2"-2.15" maximum diameter would usually work better.

Re: spruce yard

I guess lumber yards out by you don’t sell spruce framing lumber. Around here you can just go to the lumberyard and pick through the piles of 2x stock to find some clear boards. Sometimes at work I’ll come across a joist or rafter that is just so perfect I can’t bear to nail it in place. I’ll put it aside for future oar or sparmaking.

Re: spruce yard

For the past 15 years or so I have recommended that my customers use Iain Oughtred's suggested spar scantlings for lug spars and they seem to work quite well. Spar flex has to be accounted for when designing and building sails, and too much flex makes it really hard to design a sail that performs well. There is never one spar size which will be perfect in all conditions and wind strengths, but these are a pretty good compromise - holding their shape decently without adding too much weight aloft.

Suggested diameters to shoot for when building and tapering spars:

Yards - maximum diameter 1/60th to 1/64th of the spar's length in inches. Max diameter usually 40%-45% aft, tapering to around 82% at the heel end and 62% at the peak end.
Booms - maximum diameter 1/56th of the boom's length in inches, again maximum in the 40%-45% range aft, tapers to 80%-85% at the heel (tack) and 70% at the peak (clew end).

Re: spruce yard

For Sitka Spruce,
Edensaw in PT, or Compton Lumber or perhaps Crosscut in Seattle - crosscut and compton are within a couple of blocks of each other. You may end up laminating.
I agree 1 1/2" sounds a little scant for that length.

Tebbs is not going to help a fella looking for a smallish little stick or two. They sell to crosscut and comptons, and probably edensaw.

Re: spruce yard

Crosscut in Eugene always seems to have a good supply of Sitka. They have several thicknesses. Most of the boards are 12' - 16'. They will cut longer boards as long as what you don't buy is at least 6'. Furthermore, they are willing to ship between their stores at no cost. Of course it is not cheap, but good quality fir is spendy as well. Most all the boards are exceptionally straight and without flaw. In my shop it is not easy to get a straight edge on at 14' rough-sawn board. However, in the last batch I purchased only a couple of boards needed just the slightest touch-up with a hand plane and they were good to go.

Re: spruce yard

I had a spruce lugsail yard 1.5" diameter x 12' long and used it with no trouble for years. Then I decided I wanted more tension, and changed my halyard and downhaul from braided dacron to Dyneema. A few months later I had an uncontrolled gybe and the yard broke at a knot that was small enough that it should not have given trouble.

I went to the Forum (the thread is out there somewhere) and Todd Bradshaw told me my yard was too slender, and that switching to less elastic rope is often a source of trouble. I built a Douglas Fir yard 2" diameter at the midpoint and tapering at the ends. Made it from a DF 2x4, ripping off two pieces and then gluing them (epoxy) to widen out the 2"x1.5" piece I had left.

No problems since then. (But then again, I haven't had a really bad gybe, either.)

I will beg you for advice, your reply will be concise, and I will listen very nicely and then go out and do exactly what I want! (Apologies to Lerner and Lowe.)

Re: spruce yard

Maybe I should just use stretchy rope, I really hate to not use this boom since its all rounded and tapered and ready to go. I think I'll make the yard stouter per Todd's advise an them use the boom I have until it breaks.

Re: spruce yard

Have you built a birdsmouth spar? Great for a yard because it’s hollow. And I think easier than building from solid. Mostly because the taper is built in by tapering the staves before the glueup. I’ve built both side by side and the birdsmouth was easier.

Re: spruce yard

if I make the yard at 130 inches by 2 inches square, wouldn't that be too heavy for the mast.

A 2" square yard would be pretty heavy. On the other hand, 2" maximum diameter on a round-sectioned spar that tapers at both ends should not be. No, it isn't what you would think of as a particularly light piece of wood, but it is there to limit uncontrolled flexing, which does horrible things to your sail's consistent shape and efficiency.

As for the boom, the sheeting method can have a pretty substantial effect on how well it works. Some sheet block placements tend to bend the boom a lot more than others. Here again, excessive bending does not contribute very well to good sailing. Whether or not the sail is laced and attached all along the boom, or loose-footed and connected only at the tack and clew corners will also make a difference. If you apply a lot of sheet tension (especially when using mid-boom sheeting) and substantially bend the boom's middle downward, two things can happen. For the sail which is laced all along the boom, this bending defeats the foot round built into the sail and flattens the lower half of the sail. This can be good in heavy air, but it is not desirable to have boom bend robbing you of power-producing sail draft all the time because the boom is too flexible.

For the loose-footed sail, connected only at tack and clew, boom bend actually does pretty much the opposite. It moves the tack and clew corners slightly closer together, increasing the lower sail draft. In heavy air when you are sheeted in hard, you would rather be flattening the sail than giving it even more draft. So excessive bend is not so great in either scenario, but you could give the skinny boom a shot and see how it works.

The spars which have been properly tapered also tend to work better and have better flex patterns for good sail shape than untapered spars, even though the untapered spar with a full length uniform diameter will actually contain more wood.

Re: spruce yard

Originally Posted by altfj

Maybe I should just use stretchy rope, I really hate to not use this boom since its all rounded and tapered and ready to go. I think I'll make the yard stouter per Todd's advise an them use the boom I have until it breaks.

Look at your sheeting method, perhaps stay away from mid boom sheeting. Perhaps the sheet can go up to boom block, aft to another block, then down to traveller and back up to tie off to end of boom. Three points = less bend and won't break, probably.

Stretchy rope for halyards for a lugsail is annoying. As the wind builds, you will be finding yourself constantly tightening downhaul.

The taper in yard is hugely influential, as is the piece of wood you chose. I've done yards with same dim's from two piece of spruce from different trees and had very different results.

Re: spruce yard

So, since I've only sailed a boat once, this is all pretty complicated to me. I think I need a picture. Also, I tapered my boom from 1.5 down to 1 in on the last 20 inches of each end but if I taper the yard according to Oughtred's specs then I will need to taper different percentages fore and aft. I'm not even sure how I'd figure all of that out?

Re: spruce yard

Ok, very interesting, I have a lot to learn about sails. This is my first sailboat so, its all kind of confusing. Is there some book that will tell me how to determine taper on the spars and how to do it. I tapered my boom from 1.5 down to 1 inch on the last 20 inches of each end, but it sounds like I need to taper the yard from the center out on each end and to specified percentages. Is that right?

Re: spruce yard

Originally Posted by Todd Bradshaw

A 2" square yard would be pretty heavy. On the other hand, 2" maximum diameter on a round-sectioned spar that tapers at both ends should not be. No, it isn't what you would think of as a particularly light piece of wood, but it is there to limit uncontrolled flexing, which does horrible things to your sail's consistent shape and efficiency.

Todd, what is your opinion on an oval yard, oriented appropriately at the time of hoisting, of course. My spruce stock is 1 5/8" at best after thickness planing. Can always glue on strips either side to get it to 2"+ but maybe not worth it.

Re: spruce yard

I don't see why an oval yard couldn't work fine, as long as you can keep it from twisting while in use, as it's bend is likely to be drastically different if it flops over onto its side. Not having tried one, I can't really say how its flex will compare with a round-sectioned yard. It might be surprisingly similar in the oval direction. My only real experience with ovals has been fancy canoe and kayak paddle shafts, where they seem to produce the desired stiffness with less wood.

I have built a couple pairs of quick and dirty test spars, mostly to be able to hang up new sails to get a look at how they set. The spars were cut out of 2x4s and were deeper than they were thick, and they were tapered but left rectangularly-sectioned with the corners rounded off with a small round-over bit. I don't know how much side loading they would take out on the water, but they looked good enough that I would have felt OK taking them out on a boat to try them.

altfg, taper should usually be a smooth transition for the full length of a yard or boom, from our desired maximum diameter out to those diameters desired on either end. A long batten is the tool used to plan it on the stock. Masts are sometimes tapered differently, carrying much of their biggest diameter over a long section and then tapering just nearer the ends, but yards in particular tend to have long, smooth tapers. This batten, by the way, is a piece of rectangular plastic trim molding from Home Depot. They're pretty cheap and about 1" wide by 1/4" thick. They work extremely well for laying out tapers, curves when lofting out sail plans, etc.